Electric pickup for phonograph records



H. J. TOEGEL Dec. 16, 1930.

ELECTRIC PICKUP FOR PHONOGRAPH RECORDS Filed May 19, 1928 INVENTOR BY A ATTORNEY Patented Dec. 16, 1930 Q-JUNITED STATES P ENT0mm I HERBERT JOSEPH 'I'OEGEL'OF ELIZABETH, NEW JEEsEm AssIeNoE 'ro 'SPLITDORF v ELECTRICAL COMPANY, or NEWARK, NEW JERSEY EEEcTnIe PICKUP FOR rnonoennrn n coEns i Application filed May 19,

This invention relates to" an electrical pickup device for use in connection with phonograph records, and is adapted to be "used in place vof the ordinary repro'du cer "comprising a part ofthe phonograph.

Inthe'use of an electrical pickup device of the character herein described, the generating coil, within which'anelectriccurrent is setup by changes of magnetic flux through the coil due to movement of anarmature structure, is connected tothe primary of step-up transformer, thefsecondary of fwhich is connected'to the grid of anamplifying tube in an amplified set, such as is'ordinarilylused'in connection with radio circuits, and in consideration of the device herein described, this sort of a system should be considered as being used 'in' connection with' the device of this application;

0 It is therefore the object of my invention toffprovide an electrical pickup'for phonograph records Whichfishi'ghly efficient in translating the mechanicalsound record into an electrical. current having 'undulationscorrespondingto the'sou'nd impressions on the record. 7 r H i Another object'of'my inventionis to provide an electrical pickup forthe purpose dedescribed, whichthe construction is such as to u eliminate all adjustments after the device has once been assembled.

Anothenobject of n'i'ydnventionis' to provide a device of the characterdescribedwhich is relatively light and which will therefore not causethe'nee'dle to cut the records. 7

Another object of my invention is to'providdah electrical pickup which iseasy' to make fas'senible, fandi' henc'e,cheap. to

inanufa'cture.v1

jthespecification taken in'connection the annexed drawing, wherein screw in position."

2 and' of suitable magnetic material.

These other objects apparent 'to one s'kill'ed inf this"artfafterpa' study of "Figure 1 is aj'side elevation of the electr'ic al set screw for .clamp- V the "device-as 1928; Serial No. 275mg,

but with thefmagnet removed. 7

' Figure 3 is movable armaturestructure.

Figure 5 is a perspective view'of the unitary "The figures illustrating the device, aresub-' 'stantially twice the size of a satisfactory working device. I I Referring now to numbers refer to corresponding partsin the various'views, l r

; 1 's a base of non-magnetic material such asbrass', on which are mounted pole pieces I These pole piecesmaybe fastened to thebase 1'fin the detailsfwherein like any'satisfactory' manner, as by pins ltwo "for each pole piece, which preferably are of magnetic material and also act'to bring a certaln amount of magnetlc flux down to the" vicinity of the'end of the coilt'ore to be here nafter-referredto. It is pref rable to keep the reluctance of themagneti'c circuit at this point'relatively high. The pole pieces 2 and 3 arc:bent over at one. end 'and-jtapered as indicated by the numeral '5,these}tapering en ds extending toward each otherp and pass over one end of a g'eneratingcoil 6, which is thus positioned between the 'p'ole pie'ces 2 en t I Positioned on the upper side of the base and in contact with the pole pieces? and 3,.

is a magnet (which is the last thing to be positioned within this recess, is a movable structure, comprising a damping plate 8 of "suitable material, preferably of aluminum, to give' lightness,'which as illustrated is'rectangular' in shape and to whic hfis attacheda stem9, which projects upwardly through M the 'coilfand downwardly through the socket 19. The free end ofthe core stem f9 is preferably fiattened at 10 for cooperation between the taperedends 5 andthe pole pieces ble'fiiembers '11aLnd 12. I have secured exceland 3, and between the base 1 and theta pered 2 and 3 The dampener 8 is resiliently mo'unt- 1 ed within the recess13 by means of very ffiexr thecoil 6, thereby forming a'magnetic' .core

lent results by making the members 11 and 12 out of soft rubber, and these soft rubber pieces are at least somewhat longer and preferably wider than the corresponding dimensions of the member 8. The pieces 11 and 12 may be made so as to completely envelop the plate 8. The base 1 need not have a recess 13 as described, but I prefer this arrangement.

These dampener mounting pieces 11 and 12, together with the plate 8, are held in place within the recess 13 by a clamping strip 14:, having ears 15 and 16 through which screws 17 and 18 pass, and the plate 8 may be set in proper adjustment by means of these screws. The plate 8 is provided with a socket 19 through which the lower end of the core stem 9 extends, and this end has a hole'20 therein to receive a record-playing needle which is clamped into position by aset screw 21. In some cases, a rubber cap may enclose the tapered ends of the pole pieces without coming into contact with the end 10 of the core, to keep foreign material from getting into the air gap at this place.

By reason of the construction as above-illustrated and described, I'have obtained an electrical pickup which is especially efiective in obtaining the objects of the invention previously set forth, and I have found that the device is especially effective in reproducing records of the hill and dale type but of course is not limited only to use in connection with records having this characteristic.

The operation of my device is comparatively simple and readily understood. As the needle which is fastened to the socket 19 follows the record, it moves the plate 8, and at the same time shifts the core stem 9 alternate iv to and from one pole piece to the other,

thereby changing the amount and direction of the magnetic flux through the coil 6, and setting up an electrical current inthe coil, which current is amplified in the manner heretofore explained.

Having thus described my invention, what I claim is:

1. In a device of the class described, a

'base, a magnet positioned on the base, a

generating coil disposed on the base between the limbs of the magnet, a pair of pole pieces for the magnet having free ends tapered and extending toward each other over the end of said coil whichis farthest from the base, said base having a recess therein, a plate movably mounted within said recess and'having a stem projecting through the coil forming a core thereof and terminating between the tapered ends of said pole pieces, and a socket member attachedto the plate and adapted to receive a record-playing needle. V

2. In a device of the class described, a base, a magnet positioned on the base, a generating coil disposed on the base between the limbs of the magnet, a pair of pole pieces for the magnet having free ends extending over the end of said coil which is farthest from the base and turned toward its axial center, said base having a recess; a plate positioned in said recess between two pieces of flexible material and having a stem extending between said pole pieces, a clamp for holding the plate and said pieces of flexible material within the recess, and a socket member attached to the plate and adapted to receive a record playing needle.

3. In a device of the class described, a base, a magnet positioned on the base, a generating coil disposed on the base between the limbs of the magnet, a pair of pole pieces for the magnet having free ends extending over the end of said coil which is farthest from the base and turned toward its axial center, said base having a recess; a plate positioned in said recess between two pieces of soft rubber having a length and breadth at least as great as the corresponding dimensions of the plate, said plate having a stem extending between said pole pieces, a clamp for holding the plate and said pieces of flexible material within the recess, and a socket member attached to the stem and adapted to receive a record-playing needle.

4. In a device of base, a magnet positioned on the base, a generating coil disposed on the base between the limbs of the magnet, a. pair of pole pieces for the magnet having free ends extending over the end of said coil which is farthest from the base and turned toward its axial center,

a pair of pieces of flexible material, a plate positioned between said pair of pieces-and substantially enclosed thereby and havinga stem forming a core for said coil and havingv its extremity positioned between said pair of pole pieces, a clamp extending over said plate and resting against one of said pieces for adjustably mounting the said two pieces and plate to the base and a socket member attached to the plate and adapted to receive a record-playing needle,

5. In a device of the class described, a magnet, a generating coil, polepieces extending from the opposite limbs of the magnet over at least one end of the coil and terminating on opposite sides of the axial center of the coil so as to form an air gap atone end of the coil, a support member, a movable structure comprising a plate positioned adjacent the opposite end of the coil and having a stem of magnetic material projecting through the coil and into said air gap, a flexible piece of material on opposite sides of the plate and covering the entire sides and between which the plate may oscillate, a clamp extending over said plate and resting against one of said pieces for holding the plate and pieces of flexible material to the suppor and means for attaching a needle to the movable structure.

6. In a device of the class described, a magnet, a support member therefor, a generating coil carried by the support, pole pieces extending from the opposite limbs of the magnet over the end of the coil away from the support andterminating on opposite sides of the axial center of the coil so as to form an air gap, a plate positioned adjacent the opposite end of the coil and having a stem projecting through the coil and into said air gap, means for flexibly mounting the plate to the support comprising two thin pieces of soft rubber, one on each side of the 7 plate and covering the entire side and extending beyond the plate at least on two sides whereby the plate may oscillate between the said rubber piecesas pivots, a clamp extending over said plate and resting against one of said pieces for holding the plate and rubber pieces to the support, and a needle socket carried by the stem.

In testimony whereof I afiix my signature.

HERBERT JOSEPH TOEGEL. 

